Evaluation of proliferation and apoptosis markers in circulating tumor cells of women with early breast cancer who are candidates for tumor dormancy

IntroductionClinical dormancy is frequently observed in breast cancer. In the present study, we aimed to characterize circulating tumor cells (CTCs) in dormancy candidates (DC) with early breast cancer in terms of proliferation and apoptosis. Methods: Cytospins of peripheral blood mononuclear cells (PBMCs) were obtained from DC (n =122) who were disease-free for at least five years and from metastatic patients (n =40) who relapsed more than five years after surgery. Sequential samples from eight DC (n =36) who maintained a prolonged disease-free status and from eight DC (n =27) presenting late relapse during follow-up, were also analyzed. PBMCs were triple stained with a pancytokeratin, antibody along with anti-Ki67 and anti-M30 antibodies as proliferation and apoptosis markers, respectively. Results: CTCs were identified in 40 (33%) of 122?DC and in 15 (37.5%) of 40 metastatic patients. In total 25 (62.5%) DC had exclusively dormant (Ki67(-)/M30(-)), 7 (17.5%) had proliferative Ki67(+)/M30(-), 4 (10%) had apoptotic Ki67(-)/M30(+) and 4 (10%) had both phenotypes of proliferative and apoptotic CTCs. In comparison, 53.4% of CTC-positive metastatic patients had exclusively dormant and 46.6% had proliferative CTCs; none had apoptotic CTCs (P =0.039). Among all CTCs detected in DC patients, 82.4% were dormant, whereas in the non-dormant population, 32.5% were proliferative and 67.5% apoptotic. The respective percentages in metastatic patients were 59.1%, 100% and 0% (P
Source: Breast Cancer Research - Category: Cancer & Oncology Authors: Source Type: research